A group of researchers found high levels of toxic heavy metals in a community garden in Vancouver. They warn what looks like a beautiful garden may still be contaminated.

A series of tests were done to identify the metal contaminants present in the native soil from the community garden at Oak St. and 16th Ave. Results showed that the soil had high levels of lead and zinc. With concentrations reaching 219 parts per million (ppm), lead exceeds the standard set by the Canadian Council of Environment Ministers. According to experts, this discovery is important in educating the people about the risks and encouraging the city government to make an action.

Higher than the Industrial Brownfield

Results also showed that the levels of lead at the Vancouver site are five times more than the levels found at UBC Farm, a site just a few kilometers away. The total contamination in the Vancouver community garden was even higher than an industrial brownfield examined by the researchers.

“I was surprised…that this community garden which looks beautiful, contains many more metals than the brownfield,” says Oka, a UBC masters student in soil science and lead author on the study published in the Journal of Soil Science and Plant Nutrition. She added that the brownfield near the Georgia Street viaduct had obvious signs of contamination.

The Vancouver site, on the other hand, was once a restaurant and a parking lot. Its history is unclear. Oka also noted that “… much of the contamination may come from traffic at the busy street corner.”

A Potent Neurotoxin

Lead is a potent neurotoxin, which can damage the nervous system and cause brain disorders. When grown on uncontaminated soil, plants will typically have lead concentrations between 0.1 ppm and 10 ppm. Researchers found elevated levels of metals in the roots of and shoots of the bluegrass samples fromUBC Farm. Bluegrass samples from 16 Oaks contained approximately 400 ppm of lead, according to research.

Urban Farming as a Growing Trend

Vancouver has been encouraging people to build community gardens for many years. Today, there are more than 75 urban farm sites across the city. Many of them are situated along busy streets and on former industrial sites.

To Care, Not to Scare

The researchers conducted the study to inform the government and the public about the health risks soil contamination can cause. They don’t want to make gardeners afraid. They want the city to develop a plan for testing the soil health at urban gardens.

Les Lavkulich, co-author of the study and director of UBC Master of Land and Water Systems program, said in a statement that the research “has shown that the potential for metal contamination is a concern.”